Operating levers having an engine rotation rate control member in the related art include the operating lever disclosed in Japanese Patent Registration No. 2752820. This operating lever includes an operating member that is used to control an engine speed and is mounted a grip main body of a swing lever, which is not allowed to rotate, in such a manner that the operating member can rotate relative to the grip main body. This structure prevents the operating member from being inadvertently operated during an operation for swinging performed by the operator gripping the grip main body and also prevents the operating lever from being inadvertently rotated while the operating member is being operated.
The operator of a crane work machine mounted with a boom hoist drum, a main hoist drum, an auxiliary hoist drum and the like sometimes drives a plurality of drums simultaneously through a combined control of the operating lever. For instance, he may drive the boom hoist drum while also driving the main hoist drum or may drive the auxiliary hoist drum while driving the main hoist drum. It is desirable to ensure that the engine speed can be freely adjusted when controlling the drive of a plurality of drums as described above. However, it is difficult to adjust the engine speed while controlling the drive of a plurality of drums with the operating lever disclosed in the above-identified publication since the operating member is disposed at the grip main body of the swing lever. In addition, if the operating member is inadvertently operated, an undesirable fluctuation of the engine speed will result.